Directional drilling may be used in hydrocarbon well drilling for many different reasons. For example, it may be desirable to drill in a certain direction to provide multiple wells from a single location, to access geological formation areas that are inaccessible from the surface location, or to avoid undesirable formations.
In directional drilling, a driveshaft is coupled to a drill string, on an uphole side of the driveshaft, and a rotary steerable system (RSS), on a downhole side of the driveshaft. With the RSS, the drill bit is able to be steered in a desired direction using a “push-the-bit” method or a “point-the-bit” method. In the “push-the-bit” method, the driveshaft is directed to the desired direction by a reactive force imparted on the driveshaft from contact with the borehole. In the “point-the-bit” method, the driveshaft connected to the drill bit is flexed to direct the bit in the desired direction.
In the “point-the-bit” method, a reference housing through which the driveshaft extends is not connected to the driveshaft in a torsional direction to enable the driveshaft to rotate freely within the housing. This becomes a problem when the housing becomes stuck in the borehole.